Tonneau covers have been used for a number of years and used to cover the cargo box of pickup trucks and protect its interior against dirt, debris and other environmental contaminants and in some cases to improve the aesthetic quality thereof. Originally tonneau covers were designed by upholstery shops and typically made of vinyl covered fabrics or canvas. The material was often doubled over along its edges for added strength and appearance. Male snaps were then attached to the sides of the cargo box via fasteners, while female snaps were attached along the edges of the cover. Wooden bows were sometime used to span the cargo box and ensure that the cover remained high enough to drain water. Unfortunately these covers were sometimes difficult to handle, often led to corrosion around the snaps and occasionally failed to protect the cargo box.
Over the years a wide variety of covers designs have been developed, in general these covers are known as either “caps” or “tonneau covers.” Caps are typically an enclosure that extends substantially above the bed so as to increase the height of the cargo bed while a tonneau cover typically lies substantially flush with the top walls of the cargo bed without significantly increasing the height of the cargo bed.
Most tonneau cover systems today are constructed of a solid or fabric material and employ an internal support frame work which installs to the cargo bed as a one piece system. Occasionally these systems are hinged to provide an opening section thus providing access to the cargo bed to stowed cargo. Clamp methods are often employed to allow alignment and installation of the cover system to the cargo bed or when on occasions, it may be necessary to carry a load that exceeds the height limitations of the cover system, clamping methods allow quick removal of the cover from the cargo bed.
For example U.S. Pat. No. 5,636,893 discloses tonneau cover comprising of two or more hard panels pivotally connected to one another to fold in an accordion-style fashion, each of said panels having side edges overlying the upper ends of the cargo box side walls.
U.S. Pat. No. 7,334,830 discloses a tonneau cover for the cargo bed of a pickup truck which comprises of three hinge sections and whereas claims; a covering overlaying the first and second sections, and the second section being joined to the first section so as to be moveable between an extended position adjacent to the first section and a folded position overlaying at least part of the first section, wherein the second section is hinged to the first section, the second section is releasably clamped to the pickup truck when in the extended position, and the second section is releasably clamped to the first section when in the folded position, and a third section hinged to the second section, the third section is releasably clamped to the pickup truck when in the extended position, the third section is releasably clamped to the second section when in its folded position, and the second and third sections are releasably clamped to the first section when in their folded positions.
U.S. Pat. No. 7,484,788 discloses a tonneau cover for the bed of a pickup truck comprising three sections with which includes a pivot hinge having plurality of inner surfaces primary used to discourage fluids from entering into the cargo bed.
Patents illustrated disclose sectional hinges utilized for cargo bed covers with each providing improve in design for tonneau cover applications.